[ale] BASH script - wait for CD insert

[jloden at toughguy.net (Jay Loden)]

I am scripting a DVD backup solution, and the idea is for the script to email 
the admin when it is ready for the backup, then the admin puts in the DVD and 
the backup is performed.  Does anyone know of a way to eject the CD tray, 
wait for the DVD insert and then when it's inserted, continue on with the 
script (burn the backup)? 

I know how to eject the tray, but not how to wait for and detect insertion of 
the DVD. 

-Jay